Recently, with the rapid industrialization and informationization, the amount of available information increases sharply, requiring high density of information recording and reproducing devices.
The bit-patterned media has a recording layer, on which information is recorded, in patterns of bit pixels that are the recording unit of information, and is receiving the spotlight due to the high record density.
In order to achieve high recording density, two-dimensional (2D) bit-patterned media which has down-track and cross-track have been proposed. However, 2D bit-patterned media causes interference between signals in a short distance between the down-track and the cross-track.
Meanwhile, soft output Viterbi algorithm (S OVA) tracks data received through several different paths, and selects a path with highest likelihood among them, and lastly selects data of the selected path.
The conventional signal detection method of 2D bit-patterned media applies SOVA to each of the down-track and cross-track, which obtains two output values, and averages them to detects an output signal.
However, when pixels are arranged with delays between adjacent down-tracks, the conventional signal detection method which only considers the down-track direction and the cross-track direction cannot recognize all of the affected neighboring pixels.